Heretofore, lickerin screens and the like have been provided which are essentially provided with spaced screen bars which are not attachable with respect to angularity or with respect to each other. Instead, the whole unit, including side frame members are generally adjustable to vary the settings with respect to the clothed roll of the carding apparatus. Apparatus which is similar to mote knives are illustrated in connection with a beater rather than a carding machine, U.S. Pat. No. 244,393. Mote knives are illustrated in connection with a lickerin wherein the mote knives are carried by plates adjustable with respect to the lickerin as illustrated in U.S. Pat. No. 2,188,458. The prior art further includes in connection with a grid section for a beater, grid bars having adjustments for angularity and with respect to the beater, but not with respect to each other. It is desirable to provide a fiber cleaning system which is provided with independent segments which may be removable in their entirities and which have adjustment with regard to angularity, as well as with respect to each other and to the roll of a carding machine. It is also desirable that such apparatus be capable of being mounted on the back screen of the card and be provided with removable baffles beneath the segments of the screen so that air control may be possible to act in a fashion similar to that of a fiber retriever such as illustrated in U.S. Pat. No. 3,955,244. Thus, air currents may be controlled so that there is a separation of air to cause light fibers to flow back up to the lickerin while the trash passes between the segments and is not allowed to re-enter the process and is collected in a manner provided for removal. Undersirable fibers and trash are propelled by centrifugal force and separated from the surface of the lickerin by the slope of the segments.
Thus, it is important to provide a screen capable of use in connection with a carding element wherein the fibers are in open condition on the teeth as opposed to a beater wherein chokes or chunks of fibers are utilized which are not on the teeth such as illustrated in U.S. Pat. No. 2,681,478.
It is desirable in connection with finer grades of stock to utilize the baffles, whereas in connection with heavier stock, it is possible to leave out the baffles and perhaps one or more of the screen segments to increase exposed area for centrifugal force to act.
An important advantage of carding apparatus employing an assembly constructed in accordance with the invention may be noted from the fact that large quantities of waste, for example, on the order of 8-15% may be removed for reclaimation by means of a suitable reclaimation system such as another carding machine. Other waste removal systems presently employed on carding machines are capable of removing only about 2-3% of the fibers as waste. With apparatus constructed in accordance with the present invention, the space between the bars may be adjusted to take out whatever amount of fibers as waste is desirable.
A major purpose of the fiber cleaning system is to remove the highest percentage possible of very short or immature fibers which are very detrimental to good yarn quality and are particularly detrimental to dyeing, as well as while controlling the amount of short fiber which is not conducive to spinning into good wuality yarn and which should be removed for first quality work. It is also important to minimize the amount of spinnable fiber which is that fiber whose staple length allows it to be drafted evenly and spun into good quality yarn.
This is accomplished by distributing as little as possible the good fibers which are securely held by the teeth of the lickerin cloting, while at the same time using the independently adjustable segments or baffles to direct the air current existing around the lickerin and the centrifugal forces created by the rotational speed of the lickerin to remove the maximum amount of undesirable material. It is through that the useful fibers are held by the teeth of the lickerin securely and that the shorter the fiber the less securely it is held. The trash is apparently not held by the teeth but is pushed to the outer surface of the flow of material and resists the forward motion of the flow of material to some extent.